USGS Science⌕ Search
Home/Archive/USGS

USGS · sir20145190

Simulation of the Lower Walker River Basin hydrologic system, west-central Nevada, using PRMS and MODFLOW models

Kip K. Allander·Richard G. Niswonger·Anne E. Jeton
View original source ↗Read source document ↗Export metadata ↓

Abstract

Walker Lake is a terminal lake in west-central Nevada with almost all outflow occurring through evaporation. Diversions from Walker River since the early 1900s have contributed to a substantial reduction in flow entering Walker Lake. As a result, the lake is receding, and salt concentrations have increased to a level in which Oncorhynchus clarkii henshawi (Lahontan Cutthroat trout) are no longer present, and the lake ecosystem is threatened. Consequently, there is a concerted effort to restore the Walker Lake ecosystem and fishery to a level that is more sustainable. However, Walker Lake is interlinked with the lower Walker River and adjacent groundwater system which makes it difficult to understand the full effect of upstream water-management actions on the overall hydrologic system including the lake level, volume, and dissolved-solids concentrations of Walker Lake. To understand the effects of water-management actions on the lower Walker River Basin hydrologic system, a watershed model and groundwater flow model have been developed by the U.S. Geological Survey in cooperation with the Bureau of Reclamation and the National Fish and Wildlife Foundation. The watershed model was developed using the precipitation runoff modeling system (PRMS) and the groundwater flow model was constructed using the MODular groundwater FLOW model (MODFLOW) and both were calibrated for the lower Walker River Basin. These models can be incorporated in an integrated Groundwater and Surface-water FLOW (GSFLOW) model of the lower Walker River Basin. Additionally, the MODFLOW model developed for this study is useful for efficiently simulating long-term and large-scale effects of water-management actions on groundwater hydrology, streamflow, and Walker Lake level, volume, and dissolved-solids concentrations. The lower Walker River Basin PRMS model (LWR_PRMS) was constructed using a subbasin approach to aid in development and calibration, and simulates a 30-year period from 1978 to 2007 using daily time steps. The LWR_PRMS was used to estimate the distribution of groundwater recharge specified in the MODFLOW model. The highest rates of groundwater recharge occur in the Wassuk Range beneath perennial and ephemeral stream channels, whereas lower rates of recharge occur beneath alluvial fans along mountain fronts. The total groundwater recharge estimated using PRMS was about 25,000 acre-feet per year. The lower Walker River Basin MODFLOW (LWR_MF) model simulates an 89-year period using monthly time steps. The LWR_MF was constructed with an initial steady-state simulation to represent dynamic equilibrium conditions from 1908 to 1918 and then a transient simulation representing the period 1919–2007. The model was calibrated using a combination of manual and automated methods of adjusting model parameters to minimize errors between model simulated results and weighted observations of groundwater levels, streamflows, and lake level. Hydrologic conditions simulated with the LWR_MF include the movement and change in storage of groundwater, and the water budgets for Walker River, Walker Lake, and the groundwater system. The LWR_MF computed dissolved-solids concentrations for Walker Lake using simulated lake volume and an assumed constant internal salt mass of 37.2 million tons. Effects of potential changes in water management on future conditions (scenarios) of the lower Walker River Basin hydrologic system and Walker Lake from 2011 to 2070 were evaluated. Several water-management scenarios were considered, including a baseline scenario that represents no changes in system management, improved irrigation efficiencies for the Walker River Indian Irrigation Project (WRIIP), a range of increased streamflows entering the lower Walker River Basin, and, the fallowing of fields on the WRIIP. For the baseline scenario, it was assumed that streamflow conditions from 1981 to 2010 will be repeated in the future. Results indicate that Walker Lake level and volume continue to decline but at a slower rate as the surface area of the lake becomes smaller and lake evaporation decreases. Dissolved-solids concentrations in Walker Lake continue to increase and increase much more rapidly during periods when minimal flows reach the lake due to a diminished lake volume. Alternatively, in years with high runoff, lake level increases are greater and dissolved-solids decreases are greater, compared with equivalent runoffs experienced during 1981–2010. The simulated effects of improving WRIIP efficiencies on Walker River streamflows, Walker Lake inflow, level, and dissolved-solids concentrations, and crop consumptive use, are compared with the baseline reference scenario for a range of irrigation efficiency improvements from 0 to 25 percent over 60 years. Results indicate that water is conserved through a reduction in irrigation-induced groundwater recharge and subsequent groundwater discharge through evapotranspiration. The conserved water mostly goes to increased streamflow to Walker Lake, followed by increased crop consumptive use, then increased evaporation from Weber Reservoir. The simulated effects of increased streamflows at Walker River at Wabuska streamgage (10301500) on Walker Lake inflow, level, and dissolved-solids concentrations, and crop consumptive use, are compared with the baseline scenario after 60 years under two different management methods for Weber Reservoir. Results indicate Walker Lake level and dissolved-solids concentrations stabilized with increased irrigation-season streamflow of about 40,000 acre-feet per year at the Walker River at Wabuska streamgage. Walker Lake level increased, and dissolved-solids concentration decreased, with increased flows of 50,000 acre-feet per year or more. After 60 years with additional irrigation-season streamflows of 50,000 acre-feet per year, Walker Lake level increased by about 48 feet, and lake dissolved-solids concentrations decreased by about 3,000 milligrams per liter (mg/L). With 75,000 acre-feet per year of additional streamflow, Walker Lake level increased by 70 feet, and dissolved-solids concentration decreased by 7,600 milligrams per liter. The effects of fallowing of Walker River Indian Irrigation Project fields from 2007 to 2010 on Walker Lake inflow, level, and dissolved solids were evaluated. Fallowing resulted in a near doubling of Walker River inflow to Walker Lake during this period, an increase in Walker Lake level of about 1.4 feet, and a decrease in dissolved-solids concentration of about 540 mg/L.

Explore related subjects

Scientific Investigations ReportReport

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Kip K. Allander, Richard G. Niswonger, Anne E. Jeton. 2014. Simulation of the Lower Walker River Basin hydrologic system, west-central Nevada, using PRMS and MODFLOW models. https://doi.org/10.3133/sir20145190

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2026

Monitoring recreation on federally managed lands and waters—Aspects of visitor use

Federally managed public lands and waters receive around 1 billion recreational visits each year. Data on these visitors can aid in guiding policy decisions, managing resources effectively, and communicating the economic contributions of lands and waters. This report explores the methods used by agencies to collect data on aspects of recreational visitor use to Federal lands and waters (apart from visitation numbers, which are the focus of a companion publication). Aspects of recreational visitor use include visitor demographics, recreational activity participation, visitor satisfaction, visitor attitudes and experiences, trip characteristics, and economic contributions. We review practices used to understand aspects of visitor use across seven Federal agencies, revealing similarities such as the use of visitor intercept surveys and coverage of similar topic areas, and differences in how survey programs are operationalized and how specific questions on visitor surveys are worded. We also evaluate emerging technologies, such as geolocated social media and mobile device location data, for their potential to aid in understanding aspects of visitor use. This report concludes with potential opportunities to enhance data collection and coordination, ensuring cost-effective data collection and informed decision making.

Scientific Investigations Report↗
USGS2026

Evaluation of best management practices at an edge-of-field site in the Eagle Creek watershed, Ohio, 2012–20

In 2010, the U.S. Geological Survey worked in partnership with the Great Lakes Restoration Initiative and the Natural Resources Conservation Service to identify farm fields in priority watersheds—watersheds critically important to Great Lake health. Intensive best management practices were implemented in five States to test the efficacy of best management practices, also referred to as agricultural conservation practices, to reduce sediment and nutrient runoff on agricultural fields. These fields were chosen as representatives of the priority watersheds because their farming practices and geographical conditions were common among farms in those watersheds. A farm site located near Findlay, Ohio, in the Eagle Creek watershed used two conservation practices, cover crop (Natural Resources Conservation Service practice standard 340) and variable rate technology (VRT; Natural Resources Conservation Service practice standard 590), which represent common practices in the Maumee priority watershed. This study monitored surface runoff and subsurface tile runoff at the Eagle Creek watershed site. The effects of cover crop and VRT nutrient application on sediment and nutrient runoff were assessed from October 2012 to September 2020. Cover crops were applied in fall of 2016, 2017, and 2018, coinciding with VRT applications. The following parameters were analyzed as part of the study: runoff discharge; peak discharge; and concentrations and loads of total phosphorus, particulate phosphorus, dissolved reactive phosphorus, and suspended sediment. High peak runoff events disproportionally affected nutrient concentrations and loads in runoff. A threshold of the 85th percentile of the peak discharge was chosen to assess the effect of cover crop and VRT nutrient application on nutrient mitigation at each gage. Runoff events below the 85th percentile were considered small, and runoff events over the 85th percentile were considered large. Concentrations from collected water-quality samples were used for the analysis; estimated concentrations were excluded from the statistical evaluation. All surface runoff parameters during small runoff events, except surface runoff volume, were significantly lower in the period with cover crops and VRT implementation. Contrarily, subsurface runoff parameters during small events were not statistically different between the periods with and without cover crops and VRT implementation. Surface and subsurface parameters during large events were also not statistically different between the periods with and without cover crops and VRT implementation. These results indicate cover crops and VRT may improve water quality during small runoff events, but additional best management practices that mitigate large runoff events may lead to greater water-quality improvement given the contribution of large events to overall losses.

Ohio↗
USGS2026

Continuous monitoring and temporal variability of fluorescence of dissolved organic matter in karst groundwater of the Edwards aquifer, south-central Texas, 2019–24

Widespread urbanization on the Edwards aquifer recharge zone in south-central Texas has prompted the development of new approaches and tools for evaluating the current and future status of water quality in the San Antonio and Barton Springs segments of the Edwards aquifer. The U.S. Geological Survey, in cooperation with the San Antonio Water System and the City of Austin, applied continuous monitoring of fluorescence of dissolved organic matter (fDOM) to characterize the sources and transport of dissolved organic matter and associated constituents in the Edwards aquifer. Continuous fDOM time-series data were adjusted using empirically derived temperature, turbidity, and inner-filter-effect correction factors prior to analysis and interpretation. Fully corrected fDOM time-series data from the study sites were evaluated for short- and long-term temporal variability in fDOM in the context of the hydrologic and climatic conditions that occurred during the 5-year study period to understand vulnerability of the aquifer to potential contaminants in recharge. Study results indicate that fDOM is an effective proxy for dissolved organic carbon that, in turn, is indicative of the influx of recent surface water and associated contaminants, and thus, aquifer vulnerability to those contaminants. Although other continuously monitored water-quality parameters provide insights into changes in water quality in response to varying hydrologic conditions, the quantitative relation between fDOM and dissolved organic carbon directly indicates the timing and magnitude of pulses of organic constituents derived from the land surface, whereas other water-quality parameters do not.

Texas↗